Near-Infrared JHKL photometry of the symbiotic star Hen 2-147 between 1981 and 2005, monitored from the South African Astronomical Observatory (SAAO) at Sutherland. All but one observations were made on the 0.75m telescope with the MkII Infrared Photometer; the other one (on Julian Date 2446186.4) was made with the MkIII Infrared Photometer on the

Complete list of the 376 photometrically calibrated individual HII regions in the spiral galaxy NGC 628. (1 data file).

We present here a simple approach to understanding the gas cloud mass distribution function by simulating formation and destruction of gas clouds and gas clumps in the ISM. We include as relevant processes coagulation to form bigger clouds, as well as disruption by collisions and the removal of gas by collapse to form stars. We evolve initial sets

Tanto las observaciones como las simulaciones cosmológicas indican que las fusiones de galaxias son procesos bastante frecuentes en el Universo. Sin embargo, aún se desconoce la relevancia de las fusiones en la evolución galáctica y en la constitución de los bulbos actuales frente a otros posibles procesos de formación. El objetivo básico de esta

Coble defined in his 1929 treatise invariants for cubic surfaces and quartic curves. We reinterpret these in terms of the root systems of type E_6 and E_7 that are naturally associated to these varieties, thereby giving some of his results a more intrinsic treatment. Our discussion is uniform for all Del Pezzo surfaces of degree 2,3,4 and 5.

We present results for the spectral distortions of the cosmic microwave background (CMB) arising due to bound-bound transitions during the epoch of cosmological hydrogen recombination at frequencies down to ν ~100MHz. We extend our previous treatment of the recombination problem now including the main collisional processes and following the